Taking cables from a house to a garage

[ADS]

I would suspect that your ability to touch your taps when outside is quite unique and maybe you should invest in a rubber mat for outside.

Ha Ha ha,

no, it's where they're located - the sink is next to the back door so you could reach round and touch them from outside.

Can't see why you'd want to though

 

[ADS]

Seriously though,

What about these people who pop down to B&Q, by a bit of pipe and a tap, and drill straight through the wall from their kitchen taps to give themselves an outside tap - would that not be dangerous.

Another one, at my house, is that the gas feed for my boiler comes out of the house (downstairs, by the meter) and up the gable end to the first floor - you can touch this while standing on the drive way:|

So I'm not getting this 'equipotential zone' can't extend outside thing - or the introduction of a differing potential to true earth

 

[steptoe]

We weren't talking about them going "live" - you were saying about introducing a potential to the garage/shed through the CPC -

I replied that the same potential could be introduced to my taps (via

bonding) , and that I can reach them whilst standing on 'true earth' outside -

so what's the difference?

this is why Ive recently started seriously considering why its worth trying to give people advice, when they already know it anyway.

perhaps Ive mellowed somewhat during my break.

earthing is a very controversial subject, and also very subjective,

but the fact remains that it is there to minimise the risk of a potentially lethal shock,

if someone wants to take the risk of doing something less than what is considered good practice then on their head be it.

BS7671 will only save your ass to a degree, numerous quotes/professional witnesses stating good practice will soon undermine your claim to competence, 7671 does not give you a claim to being competent,

nor do having exams, they are only a method of proof until challenged. (by a court of law?)

 

[steptoe]

Seriously though,What about these people who pop down to B&Q, by a bit of pipe and a tap, and drill straight through the wall from their kitchen taps to give themselves an outside tap - would that not be dangerous.

Another one, at my house, is that the gas feed for my boiler comes out of the house (downstairs, by the meter) and up the gable end to the first floor - you can touch this while standing on the drive way:|

So I'm not getting this 'equipotential zone' can't extend outside thing - or the introduction of a differing potential to true earth

and where do you bond the gas at?

people doing DIY to an outside tap, or whatever else they want deserve all they get, (alledgedly).

obviously you dont understand the EZ, do you also think that outside influences do not apply if you have no fittings/cable outside the house?

 

[ADS]

this is why Ive recently started seriously considering why its worth trying to give people advice, when they already know it anyway.perhaps Ive mellowed somewhat during my break.

Hey, I'm not raising these questions and ideas to be argumentative or because I think I know it all.

You'll notice I haven't said to anyone "no, you're wrong"

I'm doing this to learn more and read other peoples ideas - I've already learnt from this thread, as I'm sure other people have, so no good getting all narky about it - this is what the forums are for (or so I thought)

 

[steptoe]

Hey, I'm not raising these questions and ideas to be argumentative or because I think I know it all.You'll notice I haven't said to anyone "no, you're wrong"

I'm doing this to learn more and read other peoples ideas - I've already learnt from this thread, as I'm sure other people have, so no good getting all narky about it - this is what the forums are for (or so I thought)

yes, but a search would give you all the answers to this you need,

it has been undergone at great depth previously.

and if you have something extra or different or been overlooked on previous posts then Im sure not only myself but others will be more than ready to assist.

but as it is I seem to feel myself being more and more exhausted in trying to explain the dangers of TNCS and other systems of earthing in this country.

but please look at my sig and remember,

IT is only my opinion, NOT the law, but then again, neither is BS7671 or NICEIC.

 

[bluetof]

Hey, I'm not raising these questions and ideas to be argumentative or because I think I know it all.You'll notice I haven't said to anyone "no, you're wrong"

I'm doing this to learn more and read other peoples ideas - I've already learnt from this thread, as I'm sure other people have, so no good getting all narky about it - this is what the forums are for (or so I thought)

I've had the same problem on this forum before. A lot of these guys are ' Forum ' trolls - just look at the number of posts ffs. However there is actually some good info on here. Don't take it to heart, just get the answer that you need and help others if you know something they don't. Guinness

 

[steptoe]

I've had the same problem on this forum before. A lot of these guys are ' Forum ' trolls - just look at the number of posts ffs. may be relevant to membership time . However there is actually some good info on here. Don't take it to heart, just get the answer that you need and help others if you know something they don't. Guinness

Im sorry,

but I dont regard myself as a "troll" , Im not even sure if I know what that means.

all I try and do is give an answer to the question that is asked.

but recently it seems as though a few earthing questions have been brought up that a good search of these forums would provide the answers to,

without new threads on old subjects being started once again.

without a new outlook or problem then Im pretty sure most situations with exported earths etc can be answered by previous posts on various other threads, not just by myself.

 

[ianmacd]

I've had the same problem on this forum before. A lot of these guys are ' Forum ' trolls - just look at the number of posts ffs. However there is actually some good info on here. Don't take it to heart, just get the answer that you need and help others if you know something they don't. Guinness

I do not think that is fair. IIRC the thread you are referring to was heavily modified by a moderator due to unacceptable comments, none of which came from the trolls you refer to.

 

[ADS]

.....dangers of TNCS and other systems of earthing in this country.but please look at my sig and remember,

IT is only my opinion, NOT the law, but then again, neither is BS7671 or NICEIC.

I must admit I do tend to agree with your main point - the danger of TN-C-S......I actually think it's only slightly less dangerous than TN-C.

It must be a cost issue that they use it and if proof is needed as to how dangerous it can be, you only have to ask yourself why they won't allow it in petrol stations, caravan sites etc yet they'll supply your home that way. :|

 

[spinlondon]

Although the conductivity of the Massive Earth can vary region to region, area to area. Generally there is very little difference in the area surrounding a house, or even close outbuildings.

Then there is the consideration that the impedance on a TN-C-S earth is nearly always going to be less than that of the Massive Earth.

Where it becomes a problem, is when there is a Supply neutral fault, which causes the installation earthing to become live.

If there is no reliable connection to the Massive Earth, such as when there are plastic services there will be no return path for the neutral.

A person could then introduce this return path by touching a live extraneous-conductive-part whilst in contact with the Massive Earth.

If your installation has a reliable connection to the Massive Earth, either through earthy services or a rod, this would become the return path for the neutral.

Unless there was a great difference in the conductivity of the Massive Earth in the area surrounding the house. A person touching a live extraneous-conductive-part whilst in contact with the Massive Earth, would not be in any real danger, because the neutral would be using a lower impedance path to return.

I would point out that the failure of a supply neutral is considered to be very rare, and is covered by ESQCR rather than BS7671.

At present when working to BS7671 we are not supposed to take such a fault into consideration.

Perhaps with more and more services being supplied in plastic, in future there will be a change to BS7671, and a requirement for a rod at TN-C-S installations.

 

[ianmacd]

Perhaps with more and more services being supplied in plastic, in future there will be a change to BS7671, and a requirement for a rod at TN-C-S installations.

Doubtful as its up to the DNO to supply a rod on the PEN. Maybe the ESQCR will be changed for that (better option).

A rod can be used in a TN-C-S system as I have pointed out before but BS7671 requires it to have a cable capable of taking the PFC of the installation. I personally believe it is not a good idea as it may confuse people about the actual earthing type.

 

[Andy™]

I personally believe it is not a good idea as it may confuse people about the actual earthing type.

one way of seperating the kitchen fitters from the sparks

 

[ianmacd]

[quote name='Andy

 

[Andy™]

if its that of the kitchen fitter, then yes (or just a shock will do). shouldnt play with leccy

 

[steptoe]

Although the conductivity of the Massive Earth can vary region to region, area to area. Generally there is very little difference in the area surrounding a house, or even close outbuildings.Then there is the consideration that the impedance on a TN-C-S earth is nearly always going to be less than that of the Massive Earth.

Where it becomes a problem, is when there is a Supply neutral fault, which causes the installation earthing to become live.

If there is no reliable connection to the Massive Earth, such as when there are plastic services there will be no return path for the neutral.

A person could then introduce this return path by touching a live extraneous-conductive-part whilst in contact with the Massive Earth.

If your installation has a reliable connection to the Massive Earth, either through earthy services or a rod, this would become the return path for the neutral.

Unless there was a great difference in the conductivity of the Massive Earth in the area surrounding the house. A person touching a live extraneous-conductive-part whilst in contact with the Massive Earth, would not be in any real danger, because the neutral would be using a lower impedance path to return.

I would point out that the failure of a supply neutral is considered to be very rare, and is covered by ESQCR rather than BS7671.

At present when working to BS7671 we are not supposed to take such a fault into consideration.

Perhaps with more and more services being supplied in plastic, in future there will be a change to BS7671, and a requirement for a rod at TN-C-S installations.

this is a massive problem in this country,

your PEN may only be spiked at the star point, which could be miles away,

and you now have that earth impedance in conflict with your general mass of earth at your shed.

that is why even in 16th you were required to have 30mA RCD protection on sockets for outside use.

if, TNCS was in fact always PME then such problems would be much less problematic.

 

[spinlondon]

this is a massive problem in this country,your PEN may only be spiked at the star point, which could be miles away,

and you now have that earth impedance in conflict with your general mass of earth at your shed.

that is why even in 16th you were required to have 30mA RCD protection on sockets for outside use.

if, TNCS was in fact always PME then such problems would be much less problematic.

I don't want to be seen as argumentative.

The requirement for 30mA rcd protection for sockets for use outside was due to the number of deaths associated with accidents occuring with portable appliances.

It had nothing to do with which earthing system was in use at the installation.

 

[PBC_1966]

your PEN may only be spiked at the star point, which could be miles away

But in that case the DNO won't be allowing TN-C-S, will it?

 

[steptoe]

I don't want to be seen as argumentative.The requirement for 30mA rcd protection for sockets for use outside was due to the number of deaths associated with accidents occuring with portable appliances.

It had nothing to do with which earthing system was in use at the installation.

yes it had, it was to do with the difference of potential and the disconnection device being unable to disconnest within 0.4s

But in that case the DNO won't be allowing TN-C-S, will it?

they do now.

and your point is?

this is how TNCS works.

PME and TNCS are NOT the same thing.

 

[PBC_1966]

But in that case the DNO won't be allowing TN-C-S, will it?

they do now.

They do? I hadn't realized they would allow that now. But if they are permitting it, then surely that's an argument for adding your own earth electrode, not against as you've been arguing?

and your point is?

That I still don't see your objection to the connection of an earth electrode at the installation.

this is how TNCS works.PME and TNCS are NOT the same thing.

No, but at least in the past the supply authorities would not permit TN-C-S to be used unless the network was PME.